Abnormal exhaust temperature Manual
The E030 error code on Navien boilers indicates abnormal exhaust temperature manual. Symptoms include if the overheat controller on the top of the exhaust duct is initiated, the system displays the heat, the boiler switches into lock-out, and performs post-purge continuously and operates the pump, displayed and a post-purge will be performed. → automatically cleared.
Navien E030 means: abnormal exhaust temperature manual. The usual causes are blocked or partially blocked flue system, incorrect flue installation (too many bends, excessive length) or terminal guard blocked with debris or ice. You can safely reset the boiler once — if E030 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does E030 Mean
The E030 code is shown by the boiler’s control board when it detects abnormal exhaust temperature manual. The boiler then stops instead of continuing to run in that condition: the code is the appliance reporting a problem, not proof that the boiler is broken.
| What you see on the boiler |
|---|
| If the overheat controller on the top of the exhaust duct is initiated, the system displays the heat |
| The boiler switches into Lock-Out, and performs post-purge continuously and operates the pump. |
| displayed and a post-purge will be performed. → Automatically cleared. |
| Check the output temperature displayed on the PCB. |
Common Causes
Causes documented in 2 technical sources.
| Cause |
|---|
| Blocked or partially blocked flue system |
| incorrect flue installation (too many bends, excessive length) |
| terminal guard blocked with debris or ice |
| condensate drain blocked causing back-pressure in the flue |
| combustion issue — incorrect gas/air ratio |
Safety Warning
E030 involves electrical or pressure-related components. Do not attempt repairs without proper qualifications. Ensure the boiler is electrically isolated before any inspection. If you notice water leaks, unusual sounds, or pressure anomalies, contact a qualified heating engineer immediately.
Parts & Prices
Prices shown are indicative. Actual prices and availability vary by region.
How to Fix It
Bleed the system of air
flush the heating system if sludge is present (consider a power flush)
replace the pump if it is not circulating
descale or replace the heat exchanger if blocked with limescale
open any closed valves
replace faulty thermistors
Refer to the Navien service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Navien models that can display fault code E030:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Navien models | — | Possible |
Frequently Asked Questions
Bleed the system of air. According to the technical documentation, this is the first check on the list for E030.
E030 is not classified as a high-severity fault, so the boiler can be reset once. If E030 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.